1. Technical Field
The present disclosure relates to a raw material for thermoplastic elastomers or polyurethanes, and more particularly, to a polycarbonate diol suitable for thermoplastic elastomers or polyurethanes.
2. Description of Related Art
When polycarbonate diols are used for manufacturing polyurethanes or thermoplastic elastomers as a soft segment, the polycarbonate diols enhance hydrolysis resistance, light resistance, oxidative degradation resistance, and heat resistance as well. However, because of the crystalline resulted from using 1,6-hexanediol as a reactant for polymerizing polycarbonate diol, a polyurethane using said polycarbonate diol has a drawback of exhibiting low flexibility and elastic recovery. In order to solve these problems, an aliphatic polycarbonate diol using one or more types of diols was disclosed. Among them, an aliphatic polycarbonate diol using 1,4-butanediol is reported to make the aliphatic copolycarbonate diol.
Moreover, Taiwan Pat. No. 1443125 disclosed a method to ameliorate the strength, elongation and elastic recoil of a polyurethane by adjusting the molar ratio of 1,4-butanediol to 1,6-hexanediol in the repeating units of the polymer.
On the other hand, Taiwan Pat. No. I316068 disclosed that using 3-methyl-1,5-pentanediol or trimethyl-1,6-hexanediol as a monomer to manufacture polycarbonate diol cannot ameliorate the oil resistance of the polycarbonate diol-based polyurethane but an aliphatic polycarbonate diol made from 2-methyl-1,3-propanediol and one or more diols highly enhance the oil resistance, hydrolysis resistance, and weather resistance of the polyurethane.
Therefore, to the development of a polycarbonate diol having an improved oil resistance, weather resistance and flexibility has become an urgent issue to be solved.